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dc.contributor.advisorMcLean, Robert J. C.en_US
dc.contributor.authorZere, Tesfalem Rezene ( )
dc.date.accessioned2011-12-09T17:10:59Z
dc.date.available2011-12-09T17:10:59Z
dc.date.created2011-08
dc.date.issued2011-12-09en_US
dc.identifier.urihttps://digital.library.txstate.edu/handle/10877/2539
dc.description.abstractIn their natural environments, bacteria typically are found as mixed species communities and are often attached to some type of surface. There has been considerable interest in studying bacterial biofilms; however, little is known about the mechanisms that enable them to grow as mixed populations in biofilms or planktonic communities. Recent results from the McLean laboratory on transcriptional profiles of Escherichia coli MG1655 in mixed culture with Pseudomonas aeruginosa PAO1 showed a number of E. coli genes to be upregulated including purA-F and other genes associated with purine synthesis. In contrast, genes associated with pyrimidine synthesis were unaffected. Competition experiments in both planktonic and biofilm cultures, using three purine synthesis mutants, purD, purH, and purT showed little difference in E. coli survival from the parent strain As purines are components of the cell signals cAMP and c-di-GMP, in this study we conducted competition experiments with E. coli mutants lacking adenylate cyclase (cyaA), cAMP phosphodiesterase (cpdA), and the catabolite receptor protein (crp), as well as diguanylate cyclase (ydeH) associated with c-di-GMP synthesis. Survival of the cyaA and crp mutants during co-culture were significantly less than the parent strain. Supplementation of the media with 1mM cAMP could restore survival of the cyaA mutant but not the crp mutant. In contrast, survival of the cpdA mutant was similar to the parent strain. Survival of the ydeH mutant was unaffected, suggesting that cAMP has more impact on E. coli mixed culture growth than c-di-GMP. Addition of 1 mM indole restored the survival of both the cyaA and crp mutations. Mutants in genes for tryptophan synthesis (trpE) and indole production (tnaA) showed a loss of competition and recovery through indole supplementation, comparable to the cyaA and crp mutants. Overall, these results suggest indole and cAMP as major contributing factors to E. coli growth in mixed culture.en_US
dc.formatText
dc.format.extent58 pages
dc.format.medium1 file (.pdf)
dc.language.isoen_US
dc.subjectPlanktonic
dc.subjectEscherichia colien_US
dc.subjectIndoleen_US
dc.subjectBiofilmen_US
dc.subjectCompetitonen_US
dc.subject.lcshEscherichia colien_US
dc.subject.lcshTryptamineen_US
dc.subject.lcshCyclic adenylic aciden_US
dc.subject.lcshBiofilmsen_US
dc.titleIndole and cAMP Promote Escherichia coli Survival in Mixed Cultureen_US
txstate.documenttypeThesis
dc.contributor.committeeMemberBrown, Stacie A.en_US
dc.contributor.committeeMemberAron, Gary M.en_US
dc.contributor.committeeMemberGarcia, Dana M.en_US
thesis.degree.departmentBiology
thesis.degree.disciplineBiologyen_US
thesis.degree.grantorTexas State Universityen_US
thesis.degree.levelMasters
thesis.degree.nameMaster of Science
txstate.departmentBiology


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